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      <title>Netty的传输模型 - 交互式测验</title>
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      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>Netty的传输模型 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
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  {
    "question": "根据文档，Netty传输模型的核心架构由哪三个主要组件构成，它们各自扮演什么角色？",
    "options": [
      "`BossGroup`、`WorkerGroup`和`ServerBootstrap`，它们是用于启动和配置Netty服务器的辅助类。",
      "`Channel`、`EventLoop`和`ChannelPipeline`，分别代表网络连接、事件循环和数据处理链。",
      "`Selector`、`Socket`和`ByteBuffer`，它们是Java NIO的基础组件，但不是Netty的顶层架构抽象。",
      "`Encoder`、`Decoder`和`Handler`，这些是`ChannelPipeline`中的具体处理器，是组件的一部分而非整个架构。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档明确指出，Netty的传输模型基于`EventLoop`、`Channel`和`ChannelPipeline`来处理事件和I/O操作。`Channel`代表网络连接，`EventLoop`负责执行所有I/O操作的事件循环，而`ChannelPipeline`则包含了多个`ChannelHandler`，形成数据处理链。",
    "source": "文档中「1. Netty 传输模型的架构概述」部分",
    "hint": "文档开头就概述了构成Netty异步非阻塞I/O模型的三个关键依赖组件。"
  },
  {
    "question": "在Netty中，`EventLoop`和`EventLoopGroup`之间存在什么样的关系和职责分工？",
    "options": [
      "`EventLoop`是执行I/O操作和事件的单一循环线程，而`EventLoopGroup`是`EventLoop`的容器，负责管理和分配多个`EventLoop`实例以实现并发。",
      "`EventLoop`只负责处理业务逻辑相关的任务，而`EventLoopGroup`专门用于处理网络I/O事件。",
      "`EventLoopGroup`是`EventLoop`的别名，两者在功能上完全相同，只是命名不同。",
      "`EventLoop`负责创建新的网络连接，而`EventLoopGroup`负责关闭和释放这些连接。"
    ],
    "correctAnswerIndex": 0,
    "explanation": "`EventLoop`是事件处理的核心，它在单个线程中循环处理I/O事件。为了支持高并发，Netty引入了`EventLoopGroup`，它作为一个`EventLoop`的集合或容器，可以管理多个`EventLoop`实例，并将新的`Channel`分配给其中的一个`EventLoop`进行处理。",
    "source": "文档中「2. `EventLoop` 和 `EventLoopGroup` 的实现」部分",
    "hint": "思考一下“组”（Group）和组内成员的关系，这有助于理解它们之间的协作方式。"
  },
  {
    "question": "关于Netty的`ChannelPipeline`数据处理机制，以下哪项描述是正确的？",
    "options": [
      "数据在`ChannelPipeline`中的传递是随机的，由`EventLoop`动态决定下一个要执行的处理器。",
      "`ChannelPipeline`只允许包含一个`ChannelHandler`，以保证处理流程的简洁高效。",
      "它是一个由多个`ChannelHandler`组成的链式结构，数据在其中按顺序流动，每个处理器负责特定的数据处理任务。",
      "`ChannelPipeline`只负责数据的编码（出站），而解码（入站）操作由`Channel`直接完成。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档描述`ChannelPipeline`是一个处理链，它通过一条链将多个`ChannelHandler`链接起来。当数据通过时，会按顺序经过每一个`ChannelHandler`。`fireChannelRead`等方法就是为了将数据传递给链中的下一个处理器，确保了数据流的有序处理。",
    "source": "文档中「3. `Channel` 和 `ChannelPipeline` 的数据传输流程」部分",
    "hint": "文档中反复提到`ChannelPipeline`是一个“处理链”，请思考“链”这种数据结构的特性。"
  },
  {
    "question": "Netty的`NioEventLoop`是如何利用Java NIO的`Selector`机制实现高并发I/O处理的？",
    "options": [
      "`Selector`会主动、高频率地轮询每一个注册的`Channel`，检查其是否准备好I/O操作。",
      "为每个`Channel`都创建一个独立的`Selector`实例，通过多线程并行监听来提高效率。",
      "通过调用`selector.select()`方法阻塞并监听多个`Channel`的I/O事件，当事件就绪时，通过遍历`SelectionKey`来分发处理，从而使单个线程能管理多个连接。",
      "`Selector`仅用于接受新的连接请求（`isAcceptable`），数据的读写操作则由`Channel`的同步方法阻塞完成。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档中的代码和解释清晰地展示了`NioEventLoop`的核心循环：调用`selector.select()`方法进行阻塞式等待，直到至少有一个通道就绪。然后，通过`selector.selectedKeys()`获取所有就绪事件的`SelectionKey`集合，并根据`key`的类型（如`isAcceptable`, `isReadable`）分发给相应的处理方法。这就是I/O多路复用的典型实现，允许单线程处理大量并发连接。",
    "source": "文档中「4. Netty 的 I/O 处理与 `Selector` 机制」部分",
    "hint": "思考I/O多路复用的核心思想：如何用一个“选择器”来监控多个通道，而不是为每个通道都派一个“监视员”。"
  },
  {
    "question": "Netty的“零拷贝”技术旨在解决什么问题？根据文档，它是如何通过`DefaultFileRegion`实现的？",
    "options": [
      "解决对象创建的开销问题，通过对象池技术实现，与数据传输过程无关。",
      "解决数据压缩效率问题，通过内置的压缩算法在传输前减小数据体积。",
      "解决数据在内核空间和用户空间之间多次复制的性能损耗问题，通过调用`FileChannel.transferTo()`直接在内核层面完成数据传输。",
      "解决CPU在数据传输中的高占用问题，通过DMA控制器实现完全无CPU参与的数据传输。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档中明确指出，零拷贝技术“避免了数据从内核空间到用户空间的多次拷贝”。`DefaultFileRegion`的实现示例展示了其核心方法`transferTo`，它内部调用了`FileChannel.transferTo()`。这个Java NIO方法能够直接将文件数据从文件通道传输到另一个可写通道，整个过程在内核空间完成，从而极大地提升了文件传输性能。",
    "source": "文档中「5. Netty 的零拷贝数据传输」部分",
    "hint": "“零拷贝”中的“拷贝”特指哪个层面的数据复制被避免了？"
  },
  {
    "question": "综合文档内容，以下哪项**不是**Netty实现高性能数据传输的核心机制？",
    "options": [
      "基于`Selector`的事件驱动和I/O多路复用机制。",
      "通过`ChannelPipeline`对数据进行流式和链式处理。",
      "利用零拷贝技术减少不必要的数据复制，提高传输效率。",
      "为每个网络连接创建一个独立线程的传统阻塞I/O模型。"
    ],
    "correctAnswerIndex": 3,
    "explanation": "文档通篇强调Netty是一个基于事件驱动和异步非阻塞I/O的框架。其核心优势正是通过I/O多路复用（`Selector`）让少量线程处理大量连接，这与“一个连接一个线程”的传统阻塞I/O模型是完全对立的。阻塞模型正是Netty旨在解决其性能瓶颈而设计的。",
    "source": "文档中「6. Netty 数据传输的总结」部分",
    "hint": "Netty的设计初衷是为了克服传统网络编程模型的哪些缺点？"
  }
];
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                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  